Will Lake Powell's minimum elevation be at least 3,500 but below 3,510 ft?

- [2026-10-16] Lake Powell was at 3,520.02 ft, the latest daily reading I found. It is up from a 3,518.79 ft reading on Oct 3. Daily gains of 0.1–0.5 ft over Oct 12–16, with inflow above outflow. Outflow is about 6,600 cfs. https://lakepowell.water-data.com/ - [2026-09-15] The record low for the period of record is 3,516.62 ft, set on Sep 15, 2026. This falls after the market opened on Aug 17. So the lowest reading in the window so far is about 3,516.6 ft, which is above 3,510. Source for the record: https://reservoirbench.com/lake-powell/ (a secondary site citing USBR gauge data). - [2026-08-31] End-of-August elevation was 3,517.87 ft, with 5.14 maf in storage. Reclamation's September study put the end of water year 2026 near 3,514.98 ft. The actual Sep 30 level was about 3,518.1 ft (3,518.08 ft on Sep 30 and 3,518.34 ft on Oct 1), so the lake ended the year higher than projected. https://www.usbr.gov/uc/water/crsp/cs/gcd.html and https://www.lakepowellwaterlevel.com/day/2026-10-01 - [2026-10-15] Reclamation published its October 24-Month Study. Reporting says October projections for Powell improved because of better-than-expected September precipitation. Other months are reported 5–6 ft higher than in September's report. March 2028 is projected at 3,521.54 ft. Reclamation's hydrologist says winter conditions remain uncertain and it is too early to call this substantive. I could not open the article (403). The figures come from the search snippet. https://www.8newsnow.com/news/local-news/lake-mead-projections-improve-in-new-2-year-study-less-likely-to-break-1000-feet/ - [2026-10-15] October Probable Minimum study (6.00 maf release in water years 2027 and 2028): water year 2027 unregulated inflow is 4.07 maf, or 42% of average. Powell is projected at 3,497.03 ft on Sep 30, 2027. The monthly path through March 2027 was not visible in the fetched text. https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf - [2026-09-15] September Most Probable study: Powell is projected at 3,513.51 ft on Dec 31, 2026. The lowest projected end-of-month level is 3,511.43 ft in Feb 2027. The Probable Minimum run gives 3,511.82 ft at Dec 31, 2026. A Sep 2026 snippet from a Reclamation PDF says the lake is projected to decline below 3,510 ft during water year 2027. The October study supersedes these and runs about 5–6 ft higher. https://reservoirbench.com/projections/ and https://www.usbr.gov/lc/region/g4000/24mo_6.pdf - [2026-09-29] Reporting on the Sep Probable Minimum run (a dry case that Reclamation says would be exceeded 90% of the time): Powell is near 3,516 ft at Sep 30 and about 3,503 ft by April 2027. https://www.natureworldnews.com/articles/73388/20260929/lake-powell-sits-about-28-feet-above-level-where-glen-canyon-dam-stops-generating-power.htm - [2026-08] The Operating Guidelines for 2027–28 put water year 2027 in the Low Elevation Infrastructure Protection Range. The expected Glen Canyon release is 6.00–7.00 maf. The guidelines say Reclamation will consider other tools to hold 3,510 ft and to avoid going below 3,500 ft. https://www.usbr.gov/uc/water/crsp/cs/gcd.html and https://www.usbr.gov/ColoradoRiverBasin/post2026/decision-doc/2027-2028OperatingGuidelines_Final.pdf - [2026-04-17] The April plan assumed that Flaming Gorge and other actions would lift Powell by about 54 ft, to at least 3,500 ft by April 2027. Emergency Flaming Gorge releases were underway as of June 2026. https://www.usbr.gov/newsroom/news-release/5326 and https://www.western-water.com/2026/06/17/lake-powell-faces-low-elevation-operations-in-2027/ - [2026-10-08] Water-data.com reports basin snowpack at 46.6% of average. Its Oct 16 header shows 133.7% for snowpack and 205.7% for total precipitation, which looks like a reset at the start of the water year. https://lakepowell.water-data.com/index_old.php - [Upcoming] Reclamation publishes a 24-Month Study around the 15th of each month (Nov through Mar). Spring runoff forecasts come later in winter, and the market window closes Mar 31, 2027. The lake typically bottoms out in March–April, so most of the decline risk sits after today. BOTTOM LINE: The minimum so far in the window is about 3,516.6 ft, and the lake is currently rising seasonally. The October study improved the outlook, so the lowest projected Most Probable level is probably still around or above 3,510 ft. The Probable Minimum dry case is the one that could take Powell into the 3,500–3,510 ft range or below by March. I did not retrieve the October Most Probable monthly elevations. NOT FOUND: The October 2026 Most Probable monthly Powell elevations (the 24mo.pdf URL still served the July study). The USBR data.usbr.gov RISE page value itself (I used the water-data.com and reservoirbench mirrors). Any reading after Oct 16. Any Polymarket sibling-strike prices (not searched).

- [2026-10-16] Powell was 3,520.02 ft, rising 0.23 ft that day and up about 1.7 ft from the water-year low. The inflow and release figures below are from a data aggregator. Lake Powell is 179.98 ft below full pool and is down 25.29 ft from a year ago. Outflow is about 6,600 cfs, and 10/16 inflow was 13,877 cfs. https://lakepowell.water-data.com/ - [2026-10-17] The window minimum so far (since the 2026-08-17 market open) is about 3,516.62 ft, set 2026-09-15. That is the record low for the daily series, which runs from 1963. The lowest USBR-derived value is about 3.4 ft above today's level. This is a tracker site, not USBR itself. https://reservoirbench.com/lake-powell/ - [2026-09-15] The September Most Probable 24-Month Study (median inflow, 6 maf release) has the lowest end-of-month Powell elevation at 3,511.43 ft on 2027-02-28, per a secondary site. That is 21.43 ft above the 3,490 ft minimum power pool. Month-end values can miss the daily minimum. The Most Probable path sits roughly 1.4 ft above the 3,510 line, and a non-trivial chance of a dip below 3,510 remains. https://reservoirbench.com/projections/ - [2026-10-15] The October Most Probable 24-Month Study (6 maf release) is a USBR PDF. The fetched text omitted its elevation table. Its Powell storage data (space column) bottoms around Feb–Apr 2027, with March ≈ April. It repeats that Powell is projected to decline below 3,510 ft during WY2027 . Releases are in the Low Elevation Infrastructure Protection Range. The WY2027 release is expected at 6.00–7.00 maf and may fall outside that range. https://www.usbr.gov/lc/region/g4000/24mo_6.pdf - [2026-10-15] The October Probable Minimum study (dry case, exceeded 90% of the time) has WY2027 unregulated inflow of 4.07 maf, or 42% of average. It assumes a 6.00 maf release in WY2027 and WY2028, and puts Powell at 3,497.03 ft on 2027-09-30. Reclamation says there is about an 80% probability that a future elevation falls inside the range of the minimum and maximum scenarios. https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf - [2026-09-29] A report on the September Probable Minimum run says Powell falls to about 3,503 ft by April 2027 . So even the dry case stays above 3,500 ft through the March 31 window. The same report has the dry case dipping below minimum power pool by September 2027 . The October dry run is 3,497 ft at Sep 2027, a bit lower than the September run, though I did not see its spring 2027 value. https://www.natureworldnews.com/articles/73388/20260929/lake-powell-sits-about-28-feet-above-level-where-glen-canyon-dam-stops-generating-power.htm - [2026-09 / 2026-10] The Probable Minimum run is a 90%-exceedance dry case. Its spring 2027 level was about 3,503 ft in September. Together with the median path near 3,511 ft, the window minimum probably falls somewhere in about 3,503–3,511 ft. The 3,510 line sits near the median path, while 3,500 sits below the dry case. This is my inference from the studies, not a published probability. https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf - [2026-08-22] Reclamation's August study already projected Powell would drop below 3,510 ft in WY2027. The October 1, 2026 elevation was projected below 3,540 ft, with a drop below 3,510 ft during WY2027. It projected 3,515.41 ft on Sept 30, 2026. Actual Sept 30 levels were near 3,518 ft, so the lake has run slightly above that projection. https://www.western-water.com/2026/08/22/lake-powell-faces-low-elevation-operations-in-2027/ - [2026-06 to 2026-07] The track record of earlier studies is poor, and they were far too pessimistic. The June study projected a drop to minimum power pool (3,490 ft) by spring 2027. It showed 3,498 ft by January 2027 and as low as 3,488 ft by March 2027. The July study showed a ~3,492 ft March 2027 level (The Hill). These were before drought-response actions, reduced releases and more recent runs lifted the outlook to about 3,511 ft. https://www.western-water.com/2026/06/17/lake-powell-faces-power-loss-by-spring-2027/ - [2026-04] Reclamation's stated policy aims to hold Powell at or above 3,500 ft. Actions were expected to raise Powell about 54 ft, to at least 3,500 ft by April 2027. Actions include cutting Powell releases and extra Flaming Gorge releases. Reclamation intends to keep the reservoir above 3,500 ft. This policy puts a floor under 3,500 ft, though releases can be adjusted. A secondary source describes 3,510 ft as the Interior target in the 2027–28 guidelines. https://www.usbr.gov/newsroom/news-release/5326 - [Historical base rate] Before 2026, the record low was 3,519.92 ft (2023-04-13), and the lake had never been below ~3,520 ft since filling. No close historical analogue exists for 3,500–3,510 ft. Over the last 3 years, Oct-to-spring drops from this elevation were about 5–7 ft (an aggregator estimate). That would put spring 2027 at roughly 3,513–3,515 ft before Reclamation's cuts. That estimate is crude, and it is not a USBR figure. https://lakepowelldata.com/ - [2026-10-16] Seasonal timing: the lake is currently rising slightly (October inflows were above average). Powell usually reaches its lowest point in March–April, just before the snowmelt. The window ends March 31, so the minimum may come from late March, or from an April trough that the window does not cover. https://lakepowell.water-data.com/ BOTTOM LINE: The median projection (about 3,511 ft at the end of February 2027, lowest in Feb–Apr) is close to the 3,510 threshold, and the 90%-exceedance dry case (about 3,503 ft in April 2027) stays above 3,500. The reference class therefore points to a plausible but uncertain YES. Outcomes below 3,500 ft look unlikely given the dry-case path and Reclamation's stated commitment, while an outcome at or above 3,510 ft depends on winter inflow and release decisions. NOT FOUND: The October Most Probable monthly Powell elevation table (the fetched PDF text omitted it). The Oct 2026 Probable Minimum value for March–April 2027. Any CBRFC probabilistic forecast of the window minimum. Any historical analogue for Powell at 3,500–3,510 ft.

YES means: the lowest USBR daily Lake Powell elevation from Aug 17, 2026 through Mar 31, 2027 is at least 3,500.00 ft and below 3,510.00 ft. - [2026-10-15] The October Probable Minimum study's flood-control "space" table is a new data point. Powell's beginning-of-month figure is 18,159 kaf for Oct 2026, 18,420 for Mar 2027 and 18,529 for Apr 2027. It peaks at 18,539 in May 2027. This is a 90%-exceedance dry run with 6.00 maf released. If the column is empty space, which I inferred and did not confirm, Powell would be about 260 kaf lower on Mar 1 than on Oct 1 and about 370 kaf lower on Apr 1. At my rough assumed ~40–45 kaf per ft, that is roughly 6 ft lower by Mar 1 and 8–9 ft lower by Apr 1. That would put the dry case near 3,512 ft on Mar 1 and near 3,509–3,510 ft on Apr 1. This is my arithmetic, not a published elevation. If it holds, the October dry case reaches only about the 3,510 line at the window's edge. The earlier ~3,503 ft April figure is superseded. Source: https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf - [2026-10-15] The same table shows Powell's space dipping in Nov–Dec (18,095 to 18,083 kaf) and then rising from Jan. So the dry-case trough is late winter to spring, which matches the March–April timing in the earlier reports. The window ends Mar 31, so a YES path needs the decline to cross 3,510 before then. Source: https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf - [2026-08-21] Interior's release says Reclamation will start the water year with 6.0–7.0 maf releases "to attempt to maintain" 3,510 ft or higher. It will adjust releases through April to hold 3,510. The WY2027 release volume is set in April. This is a soft target. The "attempt" language and the April decision date leave room for a dip into 3,500–3,510 before the volume is fixed. Source: https://www.usbr.gov/newsroom/news-release/5392 - [2026-08] The Record of Decision says releases switch to "run-of-river" when Powell is at 3,510 ft or lower. That is a hard operational trigger exactly at the strike. Run-of-river release (outflow set equal to inflow) stops the decline soon after 3,510 is crossed. This is the mechanism that would cap a YES path above 3,500. Source: https://www.usbr.gov/ColoradoRiverBasin/post2026/decision-doc/P26_RecordofDecision_Final.pdf - [2026-09-15] A Colorado Politics report of the Sept 15 commissioners' briefing says the 3,510 goal is a release-protection goal. The key trigger for Colorado River Storage Project releases is Powell falling below 3,500 ft. The sources describe 3,510 as a target and 3,500 as the emergency trigger, so the band between them is the managed buffer. Source: https://www.coloradopolitics.com/2026/09/15/colorado-river-managers-warn-of-worsening-conditions-looming-cuts-and-shrinking-reservoirs/ - [2026-10-05] The USBR weekly update shows Powell at 3,518.95 ft. It shows WY2026 observed unregulated inflow at only 3,719 kaf (39% of normal), and the CBRFC October inflow forecast at 120 kaf (147% of average) against the 24-Month Study's 71 kaf. The lake therefore starts winter weak, with a thin hydrologic base. Source: https://www.usbr.gov/lc/region/g4000/weekly.pdf - [2026-09-15] The September 24-Month Study (PDF) still says Powell is projected to decline below 3,510 ft during WY2027. The September run had Powell at 3,516.87 on Sept 15. Source: https://www.coloradopolitics.com/2026/09/15/colorado-river-managers-warn-of-worsening-conditions-looming-cuts-and-shrinking-reservoirs/ - [2026-09-07] Flaming Gorge releases of 660 kaf–1 maf are scheduled through April 2027. An April 2026 source says this is "a one-time thing". Winter support is therefore capped by that schedule and by Flaming Gorge's depleted storage. The extra releases end in April, so a late-March trough is not helped by any new Upper Basin water. Sources: https://www.ksl.com/article/51621145/more-water-being-released-from-flaming-gorge-to-help-lake-powell and https://coyotegulch.blog/2026/04/24/severe-coloradoriver-drought-leads-to-water-releases-from-upper-basin-reservoirs-and-reduced-flows-from-lakepowell-aspen-public-radio-coriver-aridification/ - [2026-09 to 2026-10] Single most likely path to YES: median or dry winter inflow, with 6.00 maf WY2027 releases and Flaming Gorge support running to April. Powell then drifts down from about 3,520 ft to the 3,500s by Feb–Mar 2027 and bottoms in the 3,500–3,510 band, with Reclamation's 3,510 trigger and 3,500 emergency tools stopping any further fall. Prerequisites: - Winter inflow at or below median. The September median path bottomed near 3,511 ft in Feb 2027, and the October run is reported 5–6 ft higher. - No release cut below 6.00 maf before March. - The trough occurs by Mar 31. - Run-of-river or other tools hold the lake above 3,500. BOTTOM LINE: The Probable Minimum table, read as my arithmetic, puts the 90%-exceedance dry case near 3,510 ft at the window's end and not far below it, with a policy floor at 3,510 and 3,500. So YES requires a dry-to-median winter that overcomes the October improvement, and 3,500 looks protected. The October median is reported 5–6 ft above September's, which weakens the central YES case. NOT FOUND: The October Most Probable monthly elevations (the fetched text dropped the elevation columns). A published Oct Probable Minimum Mar/Apr 2027 elevation. Any reading after Oct 16. Any CBRFC probabilistic estimate of the window minimum. Sibling-market prices (not searched).

YES means: the lowest USBR daily Lake Powell elevation between 2026-08-17 and 2027-03-31 is below 3,510.00 ft and at or above 3,500.00 ft. The case for NO is that Powell stays at or above 3,510 ft through March 31. The October 15 studies point that way for the median path and probably for the dry case too. - [2026-10-15] **Median path stays about 6 ft above the line.** The Oct 2026 Most Probable 24-Month Study (6 maf release, 1.00 maf Flaming Gorge release) has Powell's lowest end-of-month elevation at 3,516.28 ft in Feb 2027, followed by 3,516.53 ft in Mar. It then rises to 3,519.97 ft in Apr 2027. - That is far better than the September study's 3,511.43 ft low that the earlier reports cited. - The run was processed on 10/8. - https://www.usbr.gov/lc/region/g4000/24mo_6.pdf - [2026-10-15] **Monthly path to March.** End-of-month elevations are 3,519.23 (Oct), 3,519.44 (Nov), 3,518.29 (Dec) and 3,517.00 (Jan) before the Feb–Mar lows above. The median path never gets within 6 ft of 3,510 before the window closes. The study does not appear to model any shortfall, with the Flaming Gorge and Glen Canyon releases already in the run (Glen Canyon about 362–401 kaf/month). https://www.usbr.gov/lc/region/g4000/24mo_6.pdf - [2026-10-15] **Dry case, my estimate.** The Probable Minimum run (Model Run 3339, 90%-exceedance) text I could read omitted its Powell elevation table. Its Powell "predicted space" column does show the lake only modestly below the median through March: - Space is 18,296 kaf on Feb 1, 18,420 on Mar 1 and 18,529 on Apr 1, versus 18,218 / 18,257 / 18,244 in the median run. - That is roughly 285 kaf less storage than the median on Apr 1, so about 5 ft lower at about 52 kaf/ft, from the median run's own storage-to-elevation changes. - This puts the dry-case end-March level near 3,511 ft. - The estimate is crude, because bank storage and the elevation-storage curve are uncertain. I read it as about 3,508–3,512. - The dry-case trough is mostly after March, since space peaks on May 1, outside the window. - Even the dry case may therefore not cross 3,510 before March 31. - https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf - [2026-10-15] **Drivers behind the improvement.** September unregulated inflow was 0.353 maf (102% of average). The October inflow forecast is 0.400 maf (88% of average). The study counts all 1.00 maf of Drought Response Operations release from Flaming Gorge. https://www.usbr.gov/lc/region/g4000/24mo_6.pdf - [2026-10-15] **Reclamation says the gain is modest.** The 8NewsNow piece quotes the Reclamation hydrologist that winter conditions remain uncertain and it is too early to call the gain substantive. It also says Powell's low typically occurs in late February or March. That timing lines up with the window ending Mar 31. https://www.8newsnow.com/news/local-news/lake-mead-projections-improve-in-new-2-year-study-less-likely-to-break-1000-feet/ - [2026-10-16] **Status quo is rising.** The lake is at 3,520.02 ft and has risen from 3,518.79 on Oct 3, with inflow of 13,877 cfs against outflow of 6,642 cfs. It is up 1.68 ft from the water-year low, and the water year runs from Oct 1. The 3,516.62 low was set before the window's minimum candidates, so the window minimum so far is about 3,516.6 ft. A YES needs a further drop of 6.6 ft or more from the current level. https://lakepowell.water-data.com/index_old.php - [2026-10-16] **A crude historical-analogue estimate is not alarming.** The aggregator lakepowelldata.com projects about 3,514 ft by Dec 31, a 6.0 ft drop (range 4.9–7.1 ft) based on only 3 past years. That is above 3,510 at year-end. It is not a USBR figure, and it ignores the cut releases (about 6 maf for the year versus 7.48 in WY2026). https://lakepowelldata.com/ - [2026-10 (reported)] **Operators are managing to the line.** Reporting says the Flaming Gorge releases are meant to keep Powell above 3,510 ft while Glen Canyon sends 6–7 maf. Newsweek reports officials agreed to continue them through April 2027, with about 450 kaf released since April and about 550 kaf more planned. - The Oct run includes the full 1.00 maf. - Releases can be adjusted, and the guidelines let Reclamation consider other tools to hold 3,510. - Together with the stated 3,500 floor, this makes an outcome in the 3,500–3,510 band more likely to be avoided by action. - https://www.newsweek.com/lake-powell-water-crisis-emergency-water-releases-continue-12448532 - [2026-08 to 2026-10] **Past studies were too pessimistic.** The August study projected 3,515.41 ft on Sep 30 and the September study 3,514.98 ft, against an actual level near 3,518. The June and July studies were far lower (Jan 2027 near 3,498 in June). Errors have recently run in the "better than projected" direction, and the October run came in 5–6 ft higher than September's. https://www.usbr.gov/uc/water/crsp/cs/gcd.html - [2026-10-15] **Resolution mechanics.** The window ends Mar 31 and the USBR value as of Apr 15 governs, so any April trough does not count. In the Oct median run Powell is already rising in April, and the dry-case trough probably comes after March. The question needs a daily minimum of 3,500–3,510. A path that dips under 3,510 and then also under 3,500 would resolve NO, which the 3,500 floor and the dry-case trough timing make unlikely. https://www.usbr.gov/lc/region/g4000/24mo_6.pdf BOTTOM LINE: The official October median path bottoms at about 3,516 ft in Feb–Mar. My own rough estimate puts even the 90%-dry case near 3,511 ft at Mar 31, so YES needs a tail outcome (inflow worse than the 90%-dry case, or a release change) before the window closes. Status quo (lake rising, past forecasts too pessimistic, Reclamation protecting 3,510) favors NO. Note that the September study and the Reclamation text still say Powell "is projected to decline below 3,510 ft during WY 2027". That is a water-year statement, and the trough can fall after March 31. NOT FOUND: The dry-case (Probable Minimum) Powell elevation table for Feb–Apr 2027, because the fetched text omitted it, so the ~3,511 figure is my inference from the space column. Any reading after Oct 16. The USBR RISE value itself. Any CBRFC probabilistic forecast for the window minimum. Any sibling-strike prices (not searched).